Silicon doping of semipolar [formula omitted].

The effect of silicon doping on the growth and properties of ∼ 1.0 μ m - thick Al x Ga 1 - x N ( 0.50 ≤ x ≤ 0.55 ) layers grown on semipolar ( 11 2 ¯ 2 ) AlN templates by metalorganic vapour phase epitaxy was studied. The layers were grown with different disilane/group-III precursors ratios that varied from 2.8×10 −5 to 3.4×10 −4 . The surface morphology of the Si-doped ( 11 2 ¯ 2 ) AlGaN layers showed undulations along [ 1 1 ¯ 00 ] AlGaN , AlN with a root-mean square roughness of about 4.0 nm within a scan range of 20 × 20 μ m 2 . Different photoluminescence peaks have been linked to negatively charged cation vacancies ( V III 3 − ) and their complexes with impurities such as V III 3 − - 3 O N 1 + , (V III complex) 1− , and (V III complex) 2− . The optimised AlGaN:Si layer exhibited a carrier concentration of ∼1.2×10 19 cm −3 , a carrier mobility of 30.7 cm 2 /V s, and a resistivity of 0.018 Ω cm , as determined by Hall-effect measurements at room temperature. A correlation between the resistivity and luminescence emission intensities of AlGaN near-band-edge and impurity-related complexes was found. [ABSTRACT FROM AUTHOR]